Those are just some examples of what can constitute an "October surprise" — the last-minute bombshells that tend to land before Election Day and can blow apart the prevailing assumptions about who is winning a given presidential campaign.

The news Friday that the FBI discovered new emails related to its investigation into Hillary Clinton's use of a private email servre — during a separate probe into Anthony Weiner no less — certainly fits the definition of an October surprise, but it is only the latest one in what has become one of the most tumultuous elections in American history.

Even before Comey's letter threw uncertainty back into what was looking like a sure Clinton victory, this October had a few big surprises for Republican candidate Donald Trump. First, there was The New York Times revelation about Trump's $916 million loss claimed in his 1995 tax return. That was quickly overshadowed by the Access Hollywood recording that revealed some lewd comments from the GOP nominee. And that tape was followed by allegations from several women of unwanted sexual advances from Trump over the years.

Although the term "October surprise" didn't come into vogue until the late 20th century, they've been a political reality since the 1800s.

1800: Alexander Hamilton slams John Adams

The 1800 election saw incumbent John Adams go head to head with his vice president, Thomas Jefferson. It was a nasty campaign in which a Jefferson ally called Adams "a hideous, hermaphroditical character" and Adams' allies floated a rumor that Jefferson had died before the election. But, perhaps the most damaging was a 54-page letter in which fellow Federalist Alexander Hamilton slammed Adams, calling him the "enemy" and saying he had an "ungovernable temper." Adams lost the election.

1880: Garfield and the 'Chinese problem'

On Oct. 20, 1880, The New York Truth published a letter it claimed was penned by Republican James Garfield that dismissed voters' concerns that Chinese immigrants were stealing jobs from American workers. Employers had the right to "buy labor where they can get it the cheapest," the letter said. Although it was proved a fake, and the journalist responsible was later arrested, historian Joseph Cummins says the letter cost Garfield California and nearly lost him the close election against Democrat Winfield Hancock.

1912; Teddy takes a bullet

Former president Teddy Roosevelt was shot in the chest just before he was about to deliver a speech in Milwaukee as the Progressive Party candidate on Oct. 14, 1912. The bullet was slowed by the 50-page speech in Roosevelt's breast pocket, which he delivered despite his wound. His toughness, impressive as it was, didn't end up being enough to carry him back into the White House, however.

1964: Nukes blow away sex scandal

On Oct. 7, 1964, Walter Jenkins, a top aide to President Lydon Johnson, was arrested in the men's room of a Washington, D.C., YMCA and charged with disorderly conduct, allegedly for engaging in a homosexual act. Johnson asked for Jenkins resignation and feared that the scandal could cost him "the ballgame." But, in the weeks that followed, Soviet leader Nikita Khrushchev was ousted and China conducted its first nuclear test, overshadowing the Jenkins story. Johnson won in a landslide.

1972: Peace is at hand

On Oct. 26, 1972, Richard Nixon's national security adviser, Henry Kissinger, held a press conference announcing that "peace is at hand" in the Vietnam War after apparent progress in talks with North Vietnam. The talks fell apart in December of that year and the war raged on until after Nixon had left the White House, but Kissinger helped drown out news of the budding Watergate scandal and ensure Nixon's decisive re-election victory over George McGovern.

1980: Hostages and conspiracy theories

When Iran announced just days before Election Day that it would not release the Americans being held hostage until after the 1980 election, conspiracy theories quickly sprouted. They asserted Ronald Reagan had cut a deal with Iran because he feared a deal to release the hostages would seal Jimmy Carter's re-election. The hostages were released moments after Reagan was inaugurated, but two congressional investigations found no proof of a conspiracy.

1992: A fresh Iran-Contra arrest

President George H.W. Bush likely thought the Iran-Contra affair — in which the Reagan administration used the money from illegal arms sales to Iran to fund right-wing guerrillas in Nicaragua — was a thing of the past before former secretary of Defense Caspar Weinberger was indicted on charges related to the scandal just four days before the election. Bush lost the election but pardoned Weinberger before he left office.

2000: An old DUI arrest

Technically, this one was a November surprise. On Nov. 2, 2000, five days before Election Day, Fox News reported that George W. Bush had been arrested for drunk-driving in 1976. Although Bush defeated Al Gore despite the news, Bush strategist Karl Rove has claimed the election would not have been so close if the story hadn't surfaced so late in the campaign.

2012: Hurricane Sandy lifts Obama

In this case, the disaster to strike the presidential campaign was a natural one. Hurricane Sandy tore along the East Coast in the final days of October, causing major damage, particularly in New York and New Jersey. The disaster gave Obama the chance to look presidential as he dealt with the emergency, and he got a bipartisan boost from Republican New Jersey Gov. Chris Christie who worked with the president in Sandy's wake.